11.3.2.2. Arid and Semi-Arid Asia

The major impact of climate change in arid and semi-arid Asia is likely to
be an acute shortage of water resources associated with significant increases
in surface air temperature. Conservation of water used for irrigated agriculture
therefore should be given priority attention. With increased evapotranspiration,
any adaptation strategy in agriculture should be oriented toward a shift from
conventional crops to types of agriculture that are not vulnerable to evapotranspiration
(Safriel, 1995). These strategies entail either intensive agriculture in greenhouseswithin
which rates of evapotranspiration are much reducedor developing alternatives
such as aquaculture that will partly replace agriculture (e.g., fish for human/animal
feed, crustaceans for human feed, and unicellular algae for fish/prawn feed,
as well as for food additives and medicinal and cosmetic uses). All of these
organisms are of high yield; they enjoy solar radiation and often heat, and
they do not evaporate or transpire water. Expansion of commercial and artesian
fisheries also could help reduce dependence on food productivity. Protection
of soils from degradation should be given serious consideration.

Climate change would exacerbate threats to biodiversity resulting from land-use/cover
change and population pressure in Asia. Ecosystem services can be impaired by
loss of key species in arid and semi-arid Asia (Xiao et al., 1998). Because
intraspecies variation in response to environmental stress usually exists in
populations subjected to year-to-year climate change, some genotypes in such
populations are expected to be more resistant to climate change than others.
Such genotypes are more common in peripheral populations than in core populations
of species. Although the core population may become extinct because of global
warming, resistant types in peripheral populations will survive and can be used
to rehabilitate and restore affected ecosystems (Safriel et al., 1994; Kark
et al., 1999). The geographic locations of the peripheral species population
usually coincide with climatic transition zones, such as at the edges of drylands
or along the transition between different types of drylands. Many countries
in the region have more than one dryland type and hence should have peripheral
populationsespecially in desert and nondesert transitions, which often
occur within semi-arid drylands. Identifying regions with concentrations of
peripheral populations of species of interest and protecting their habitats
from being lost to development therefore can play a role in enhancing planned
adaptation for natural and semi-natural ecosystems.